[cairo] Re: cairo_get_current_point bug ?

Jamey Sharp jamey at minilop.net
Fri Sep 22 13:23:44 PDT 2006


On Fri, Sep 22, 2006 at 12:49:51PM -0700, Carl Worth wrote:
> On Thu, 14 Sep 2006 16:59:11 -0700, "Mike Emmel" wrote:
> > -void
> > +cairo_status_t
> >  cairo_get_current_point (cairo_t *cr, double *x_ret, double *y_ret)
> 
> Behdad just mentioned that it's too late to do this. From an API
> point-of-view, there would obviously be no problem, but presumably
> changing the stack like that would not allow us to provide the ABI
> compatibility we've promised.

That seems like an interesting question. Are there any platforms
(capable of running Cairo) that return an int on the stack, or do they
all return such values in registers? More importantly, is the calling
convention ever different for functions that return void versus those
that return int?

K&R compilers couldn't have distinguished this case, I think, and I have
the impression that calling conventions haven't changed much since K&R
days. So it seems to me that this change actually would be ABI
compatible everywhere. If this is the cleanest fix for this problem,
perhaps more research should go into this question.

--Jamey
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